Mike Dolt Enterprises
Mike Dolt Enterprises
User: exp, Location: SF Bay Area
Asked on: Saturday, March 1, 2025 at 2:44 am EST
Answered on: Thursday, March 6, 2025 at 9:14 am EST
Question: Hoping to find some people with historic knowledge here.Today I found what I think is the original main service panel hidden in a wall cavity of my 1929 house in the Bay Area.People have pointed out this was a larger appliance disconnect and can’t be service because it’s just 120V.However, the box was found in an abandoned external wall cavity right next to the service entrance. It’s clear that it was a wooden enclosure with an exterior door and that door has been removed, replaced with plywood and out stucco over.In this cabinet it not much room for more than this one panel. On the panel side is a thick iron conduit which goes outside. It is exactly where the service enters now. From the top, abandoned K&T exists that has been capped a bit farther downstream.The location of the cabinet is the corner of the living room where definitely no appliances were.All of this makes me very strongly believe that this was the original fused main service disconnect and from there, a K&T run went to another sub panel.Were there 120V/30A services in the Bay Area which would make this a plausible explanation?PS: in the pictures I enter the cabinet from the back. I found it while installing new ductwork and removing the piece of wood which used to be the backside of the cabinet.
You've presented a compelling case for this being the original main service disconnect. Let's break down why it's plausible and address the common concerns
Why it COULD be the original Main:
Location, Location, Location
This is the strongest argument. Being right next to the service entrance conduit is a HUGE clue. The fact that the conduit goes directly to the current service entrance is almost conclusive.
Wooden Enclosure & Original Door Impression
Houses of that era commonly had main service panels (especially fused panels) in wooden boxes. The stucco over the plywood is a good sign it's very old.
K&T Origin
The abandoned K&T capped nearby strengthens the argument. This ties it to the original wiring system.
Placement
Being on the corner in the living room sounds odd, but consider this. Original wiring runs often took the shortest path, and wall access may have been easier than through ceilings.
Why the Doubts & How to Reconcile
120V Only (Apparent)
This is the biggest hurdle. The standard today is 240V for a whole house. However, in 1929, 120V was more common, especially in smaller homes or homes that weren't heavily reliant on electric appliances.
Possible Explanations for 120V (If it's truly only 120V)
Very Small House/Apartment
If the original house was very small (think cottage or small apartment), a 120V/30A service might have been sufficient. Lighting, a small radio, and maybe an early electric iron or toaster.
Gas Appliances
Most homes had gas appliances in 1929, therefore didn’t need much amperage.
30A Rating
30A seems small, but consider the low power consumption of the day. Incandescent lights were far less efficient, and there were fewer electrical gadgets overall.
How to Strengthen Your Case
Examine the Conduit
Can you trace the iron conduit from the original box to where it enters the house? Take pictures that clearly show the conduit run. This is the key piece of evidence.2.
Professional Confirmation
At this point, you really need a qualified, experienced electrician who understands older homes and electrical systems. Show them your findings and ask for their professional assessment. Don't settle for an electrician who only works on modern systems.3.
Research Old Electrical Codes
Local historical societies or libraries might have records of electrical codes from the 1920s. See if they mention 120V services and typical amperage ratings.4.
Check Your City's Building Permit Records
The city might have records from your house’s construction that could indicate the type of electrical service installed.
Bottom Line
It's entirely plausible that this was the original main service disconnect, especially given its location and relationship to the conduit and K&T wiring. The 120V/30A rating isn't automatically a disqualifier, considering the era and potential limitations of the original electrical needs.
Important Safety Notes
Do not energize or tamper with any of the old wiring yourself. This is dangerous. Have a qualified electrician inspect and address any safety concerns. If you decide to abandon the old wiring completely, have it disconnected at the source by a professional.
Good luck with your investigation! This is a fascinating piece of your home's history. Flag for review